[gcc r14-4862] SH: Fix PR 111001

[Oleg Endo <olegendo@gcc.gnu.org>]

https://gcc.gnu.org/g:267e369afbb963d8d84d7a9f0cb9fb18672d99a8

commit r14-4862-g267e369afbb963d8d84d7a9f0cb9fb18672d99a8
Author: Oleg Endo <olegendo@gcc.gnu.org>
Date:   Mon Oct 23 22:08:37 2023 +0900

    SH: Fix PR 111001
    
    gcc/ChangeLog:
    
            PR target/111001
            * config/sh/sh_treg_combine.cc (sh_treg_combine::record_set_of_reg):
            Skip over nop move insns.

Diff:
---
 gcc/config/sh/sh_treg_combine.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/gcc/config/sh/sh_treg_combine.cc b/gcc/config/sh/sh_treg_combine.cc
index 9f6a89fa71fb..9b35960c8c2b 100644
--- a/gcc/config/sh/sh_treg_combine.cc
+++ b/gcc/config/sh/sh_treg_combine.cc
@@ -729,7 +729,14 @@ sh_treg_combine::record_set_of_reg (rtx reg, rtx_insn *start_insn,
 	}
       else if (REG_P (new_entry.cstore.set_src ()))
 	{
-	  // If it's a reg-reg copy follow the copied reg.
+	  // If it's a reg-reg copy follow the copied reg, but ignore
+	  // nop copies of the reg onto itself.
+	  if (REGNO (new_entry.cstore.set_src ()) == REGNO (reg))
+	    {
+	      i = prev_nonnote_nondebug_insn_bb (i);
+	      continue;
+	    }
+
 	  new_entry.cstore_reg_reg_copies.push_back (new_entry.cstore);
 	  reg = new_entry.cstore.set_src ();
 	  i = new_entry.cstore.insn;